// Protocol Buffers - Google's data interchange format
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// Copyright 2012 Google Inc. All rights reserved.
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// https://developers.google.com/protocol-buffers/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// This file is an internal atomic implementation, use atomicops.h instead.
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#ifndef GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_GENERIC_C11_ATOMIC_H_
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#define GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_GENERIC_C11_ATOMIC_H_
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#include <atomic>
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namespace google {
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namespace protobuf {
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namespace internal {
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// This implementation is transitional and maintains the original API for
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// atomicops.h. This requires casting memory locations to the atomic types, and
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// assumes that the API and the C++11 implementation are layout-compatible,
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// which isn't true for all implementations or hardware platforms. The static
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// assertion should detect this issue, were it to fire then this header
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// shouldn't be used.
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//
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// TODO(jfb) If this header manages to stay committed then the API should be
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// modified, and all call sites updated.
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typedef volatile std::atomic<Atomic32>* AtomicLocation32;
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static_assert(sizeof(*(AtomicLocation32) nullptr) == sizeof(Atomic32),
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"incompatible 32-bit atomic layout");
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inline void MemoryBarrierInternal() {
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#if defined(__GLIBCXX__)
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// Work around libstdc++ bug 51038 where atomic_thread_fence was declared but
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// not defined, leading to the linker complaining about undefined references.
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__atomic_thread_fence(std::memory_order_seq_cst);
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#else
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std::atomic_thread_fence(std::memory_order_seq_cst);
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#endif
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}
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inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
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Atomic32 old_value,
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Atomic32 new_value) {
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((AtomicLocation32)ptr)
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->compare_exchange_strong(old_value,
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new_value,
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std::memory_order_relaxed,
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std::memory_order_relaxed);
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return old_value;
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}
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inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
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Atomic32 new_value) {
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return ((AtomicLocation32)ptr)
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->exchange(new_value, std::memory_order_relaxed);
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}
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inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
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Atomic32 increment) {
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return increment +
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((AtomicLocation32)ptr)
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->fetch_add(increment, std::memory_order_relaxed);
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}
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inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
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Atomic32 increment) {
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return increment + ((AtomicLocation32)ptr)->fetch_add(increment);
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}
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inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
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Atomic32 old_value,
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Atomic32 new_value) {
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((AtomicLocation32)ptr)
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->compare_exchange_strong(old_value,
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new_value,
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std::memory_order_acquire,
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std::memory_order_acquire);
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return old_value;
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}
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inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
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Atomic32 old_value,
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Atomic32 new_value) {
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((AtomicLocation32)ptr)
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->compare_exchange_strong(old_value,
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new_value,
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std::memory_order_release,
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std::memory_order_relaxed);
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return old_value;
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}
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inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
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((AtomicLocation32)ptr)->store(value, std::memory_order_relaxed);
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}
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inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
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((AtomicLocation32)ptr)->store(value, std::memory_order_relaxed);
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MemoryBarrierInternal();
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}
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inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
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((AtomicLocation32)ptr)->store(value, std::memory_order_release);
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}
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inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
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return ((AtomicLocation32)ptr)->load(std::memory_order_relaxed);
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}
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inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
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return ((AtomicLocation32)ptr)->load(std::memory_order_acquire);
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}
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inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
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MemoryBarrierInternal();
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return ((AtomicLocation32)ptr)->load(std::memory_order_relaxed);
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}
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#if defined(GOOGLE_PROTOBUF_ARCH_64_BIT)
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typedef volatile std::atomic<Atomic64>* AtomicLocation64;
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static_assert(sizeof(*(AtomicLocation64) nullptr) == sizeof(Atomic64),
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"incompatible 64-bit atomic layout");
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inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
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Atomic64 old_value,
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Atomic64 new_value) {
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((AtomicLocation64)ptr)
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->compare_exchange_strong(old_value,
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new_value,
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std::memory_order_relaxed,
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std::memory_order_relaxed);
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return old_value;
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}
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inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
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Atomic64 new_value) {
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return ((AtomicLocation64)ptr)
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->exchange(new_value, std::memory_order_relaxed);
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}
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inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr,
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Atomic64 increment) {
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return increment +
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((AtomicLocation64)ptr)
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->fetch_add(increment, std::memory_order_relaxed);
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}
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inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
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Atomic64 increment) {
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return increment + ((AtomicLocation64)ptr)->fetch_add(increment);
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}
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inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
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Atomic64 old_value,
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Atomic64 new_value) {
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((AtomicLocation64)ptr)
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->compare_exchange_strong(old_value,
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new_value,
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std::memory_order_acquire,
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std::memory_order_acquire);
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return old_value;
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}
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inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
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Atomic64 old_value,
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Atomic64 new_value) {
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((AtomicLocation64)ptr)
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->compare_exchange_strong(old_value,
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new_value,
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std::memory_order_release,
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std::memory_order_relaxed);
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return old_value;
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}
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inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
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((AtomicLocation64)ptr)->store(value, std::memory_order_relaxed);
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}
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inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
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((AtomicLocation64)ptr)->store(value, std::memory_order_relaxed);
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MemoryBarrierInternal();
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}
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inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
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((AtomicLocation64)ptr)->store(value, std::memory_order_release);
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}
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inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
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return ((AtomicLocation64)ptr)->load(std::memory_order_relaxed);
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}
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inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
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return ((AtomicLocation64)ptr)->load(std::memory_order_acquire);
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}
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inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
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MemoryBarrierInternal();
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return ((AtomicLocation64)ptr)->load(std::memory_order_relaxed);
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}
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#endif // defined(GOOGLE_PROTOBUF_ARCH_64_BIT)
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} // namespace internal
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} // namespace protobuf
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} // namespace google
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#endif // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_GENERIC_C11_ATOMIC_H_
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